Board level Electromagnetic Interference (EMI) noise could be emitted from optical cages when the optics modules are unplugged from ports of the optical cages. This can cause serious failure issues. One solution is to insert blank modules into unoccupied optical cages. The blank modules are metal parts that have to establish good contact with optical cages. However, a user may forget to install blank modules or use plastic blank modules for unplugged optical ports of optical cages, which may result in failure issues due to EMI.